sheffield



(No Model.)

' L. T.ISHEPPIELD.'

DENTAL ENGINE.

No. 408,439. Patented Aug. 6, 1889.

N. PEYEns. Plmlo-Lithngnpher, Washingknn, I). c.

' screws H K.

UNITED STATES PATENT OFFICE.

LUCIUS T. SHEFFIELD, OF NElV YORK, N. Y.

DENTAL ENGINE.

SPECIFICATION forming part of Letters Patent No. 408,489, dated August6, 1889.

Application filed July 6, 1888. Serial No. 279,175. (No model.)

To all whom it may concern:

Be it known that I, LUcIUs T. SHEFFIELD, of the city, county, and Stateof New York, have invented a new and useful Improvement in DentalEngines, of which the following is a full, true, and exact description,reference being had to the accompanying drawings.

My invention relates to a simplified form of dental engine by means ofwhich the struct ure can be greatly cheapened and the backlash of thetool holder to a great extent avoided.

My apparatus will be readily understood from the accompanyingdrawings,in which-- Figure 1 represents an elevation; Fig. 2, a sectionof the engine proper, showing the attachment of the flexible cable; Fig.3, the flexible cable; Fig. 4, a detail of the sectional View of themechanism for connecting the fly-wheel with the driving mechanism; Fig.5, a sectional view through the adjusting mechanism at right angles toFig. 4, and Figs. 6 and 7 views of a modification.

My drawings show a fiy-wheel A mounted upon a suitable framework anddriven by a treadle B. The tool-driving mechanism consists of a rotatingshaft 0, to the upper end of which the cable D is attached. The shaft Cis driven, preferably, by frictional contact with the side of thefiy-wheel A, the lower end of the shaft 0 being provided withafrictionroller E. The friction. or pressure between the friction-rollerE and the side of the flywheel A can be readily adjusted by themechanism shown in Figs. 4 and 5, in which the shaft 0 is shown as heldin the divided bearing F G, capable of being adjusted by set Byloosening the screw K and screwing in the screw H any desired amount offriction can be obtained.

Instead of using a frictional contact a gear contact can be employed, asshown at E, Figs. 6 and 7. The cable itself is made tapering, as shown,by means of which backlash is avoided. This tapering form, which is ofgreat importance, can be arranged in several ways. Tapering cores may beprovided within the cable made of rawhide, whalebone, or other flexiblematerial, and the cable-wires may be laid upon the same, being wound inopposite directions alternately until the requisite size is built up; ora tapering form can be arranged by starting with a number of wire coils,which of course are wound alternately in different directions, andcontinuing the entire number for a distance, and then diminishing thenumber of coils by one consecutively until the smallest desired diameter is obtained. Of course the cable is in any event provided with anexternal cover L.

What I claim as my invention, and desire to secure by Letters Patent, is

. 1. The combination, in a motor for rotating a tool or drill, of adriving-shaft, a cable taperin g from said (1 riving-shaft toward thetool-holder, and a tool-holder rotated by said tapering cable,substantially as described.

2. The combination, in a motor for rotating a tool or drill, of adriving-shaft, a cable tapering from said driving-shaft toward thel100ll10ld6l,Et flexible tapering sheath or cover inclosing said cable,and a tool-holder rotated by said tapering cable, substantially asdescribed.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

LUCIUS T. SHEFFIELD. \Vitnesses:

ANTHONY GREF, WM. A. PoLLocK.

